Revert "Revert of create shaderproc for nofilter-opaque-dx (patchset #7 id:120001 of https://codereview.chromium.org/664783004/)"

This reverts commit 430b795cc8a1cdbddd8fdc5511a3a523348937f7 and adds suppressions.

BUG=skia:

Review URL: https://codereview.chromium.org/673023002
Fix imagemagnifier GM quality and speed.

The imagemagnifier GM was applying the filter both to a saveLayer()
restore() around the whole scene, as well as to each individual
text draw.

Applying the filter only in the saveLayer() makes it run ~20x faster
on my Linux box, and the quality is improved as well (since the
primitives are not double-filtered).

BUG=skia:

Review URL: https://codereview.chromium.org/637283009
squelch filterindiabox too

TBR=bsalomon@google.com

BUG=skia:

Review URL: https://codereview.chromium.org/677463003
Add flag to skimage for decoding into unpremul.

Review URL: https://codereview.chromium.org/666073006